Well, the first question is, is the voice over necessary for the SCP to work? If it doesn't, you would be causing yourself to have a worse time than you need to. Second, I suggest that you go through the entire article writing stages first. You need to make sure that everything is finalized before recording anything.
If your asking about voice actors, you need to make arrangements and agreements yourself with the voice actors, and then credit them in the author post, just as a courtesy.
I don't think there is anything in particular you really need to worry about, rules-wise. There are no rules against having recordings in articles, hell, there is a short movie in a series IV article.
But what you might want to do is, after you have finalized all the writing, ask a staff member to save a number slot so you can be sure of the number in the recording.
Hope this helps, best of luck.
